Saw blade for hand-held tools

ABSTRACT

In a saw blade for power tools, in particular for power reciprocating saws, with a blade back ( 11 ) and a toothing ( 12 ) extending along the lower edge of the blade back and comprising many saw teeth ( 13 ) lined up in succession, in order to increase the blade life and service life of the saw blade, especially in a thick, stable embodiment, the saw teeth ( 13 ) in successive portions (a, b) of the toothing ( 12 ) are embodied with the same tooth width (a z , b z ), which however differs from that of the saw teeth ( 13 ) in the preceding or the succeeding portion (b, a) of the toothing ( 12 ).

PRIOR ART

[0001] The invention relates to a saw blade for power tools, inparticular for power reciprocating saws, such as saber or piercing saws,of the type defined by the preamble to claim 1.

[0002] Known saw blades of this type have the same tooth width over thelength of the teeth, and this tooth width is dictated by the thicknessof the saw blade. For free-cutting of the saw blade, the saw teeth aretransposed in the workpiece, so that the tooth tips protrude laterallyslightly past the contour of the blade back in alternation. For rough,heavy-duty use, stable saw blades up to 1.6 mm thick are used, but withincreasing saw blade thickness the blade life and the service life ofthe saw blades decrease.

ADVANTAGES OF THE INVENTION

[0003] The saw blade of the invention has the advantage that by thepartial reduction of individual saw teeth, or pairs or groups of sawteeth, a very good blade life and service life of the saw blade areattained despite a thick, stable saw blade. The cutting forces areoptimized, and the heat production at the saw blade during sawing isreduced.

[0004] By the provisions recited in the other claims, advantageousrefinements of and improvements to the saw blade defined by claim 1 arepossible.

[0005] In one advantageous embodiment of the invention, the tooth widthof the saw teeth in one set of portions of the toothing is equivalent tothe thickness of the blade back, and the tooth width differing from itof the saw teeth in the other portions of the toothing is brought aboutby material removal or material compacting, such as swaging. To thatend, recesses spaced apart from one another are made in the blade backon both sides of the blade back and extend past the saw teeth as far asthe underside, remote from the blade back, of the teeth, and therecesses on one side of the blade back and the recesses on the otherside of the blade back are disposed offset from one anotherlongitudinally of the saw blade.

[0006] In alternative embodiments of the invention, the recesses areextended as far as the upper edge, remote from the teeth, of the bladeback, or they end at a distance in front of this upper edge.

[0007] In an advantageous embodiment of the invention, the recesses areinclined relative to the teeth at an acute angle in the advancementdirection of the saw blade, and preferably the acute angle is equivalentto the rake angle of the saw teeth. Because of the oblique edges of thechannels formed by the recesses, an additional advancement force againstthe workpiece ensues, because of the frictional forces.

DRAWING

[0008] The invention is explained in further detail in the ensuingdescription in terms of exemplary embodiments shown in the drawing.Shown are:

[0009]FIG. 1, a side view of a saw blade for a power reciprocating saw;

[0010]FIG. 2, a section take along the line II-II in FIG. 1, shownenlarged;

[0011]FIG. 3, a fragmentary view from below of the saw blade in thedirection III in FIG. 1, shown enlarged;

[0012]FIG. 4, a fragmentary side view of a saw blade in a furtherexemplary embodiment;

[0013]FIG. 5, a section taken along the line V-V of FIG. 4, shownenlarged;

[0014]FIG. 6, a fragmentary side view of a saw blade in a thirdexemplary embodiment;

[0015]FIG. 7, a section taken along the line VII-VII of FIG. 6, shownenlarged.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0016] The saw blade for a power reciprocating saw (saber saw, piercingsaw or the like) shown in side view in FIG. 1, as an exemplaryembodiment for a power tool in general, has a blade back 11 and atoothing 12, extending along the lower edge of the blade back andcomprising many saw teeth 13 lined up in succession. In successiveportions a and b (FIG. 3) of the toothing 12, each with an integralnumber of saw teeth 13, the saw teeth 13 are embodied with the sametooth width a_(z) or b_(z), which however differs from that of the sawteeth 13 in the preceding or succeeding portion b or a, respectively. Inthe exemplary embodiment of FIGS. 1-3, the portions a of the toothing 12each include one saw tooth, while the portions b of the toothing 12 eachinclude two saw teeth 13. The tooth width a_(z) of the saw teeth 13 inthe portions a is equivalent to the thickness of the blade back 11,while the tooth width b_(z) of the saw teeth 13 in the portions b bycomparison is smaller and is brought about by material removal ormaterial compacting. The material removal or material compacting is donein alternation from one side and the other of the blade back 11 insuccessive portions b of the toothing 12 that have the saw teeth 13 withthe reduced tooth width b_(z). To that end, on both sides of the bladeback 11, recesses 14 and 15 spaced apart equally from one another aremade; they extend past the saw teeth 13 as far as the underside of thetoothing 12, remote from the blade back 11. The recesses 14 on one sideof the blade back 11 are offset longitudinally of the saw blade from therecesses 15 on the other side of the blade back 11.

[0017] In the exemplary embodiment of the saw blade of FIGS. 1-3, therecesses 14 and 15 extend as far as the upper edge 111, remote from thetoothing 12, of the blade back 11 and are inclined in the advancementdirection of the saw blade by an acute angle α (FIG. 1) compared to thetoothing 12. The angel α is equivalent to the rake angle of the sawteeth 13.

[0018] Once the recesses 14, 15 have been made in order to reduce thesaw teeth 13 to the tooth width b_(z), the saw teeth 13 with the reducedtooth width b_(z) in each portion b of the teeth are transposed; thetransposition is done from the side of the blade back 11 remote from therespective recess 14 and 15. Overall, the saw teeth in successiveportions b of the toothing 12 are thus transposed in oppositedirections. The saw tooth 13 that is present in the portions a of thetoothing 12, having the tooth width a,, is not transposed and is flushwith the lateral contours of the blade back 11.

[0019] The second exemplary embodiment of the saw blade, shown in FIGS.4 and 5, differs from the saw blade described above only in thatrecesses 14′, 15′ that reduce the saw teeth 13 to the tooth width b_(z)in both sides, remote from one another, of the blade back 11 do notextend over the full height of the blade back 11 but instead end at arelatively great distance before the upper edge 111 of the blade back11. The recesses 14′, 15′ are again inclined relative to the toothing12, and the direction of inclination and the angle of inclination areselected as in FIG. 1.

[0020] In the third exemplary embodiment of a saw blade, in FIGS. 6 and7, the recesses 14″ and 15″ on both sides of the blade back 11 again endat a great distance from the upper edge 111 of the blade back 11. Therecesses 14″ and 15″, which as in the two exemplary embodimentsdescribed above are disposed equidistantly in the same way, now howeverextend at a right angle to the longitudinal direction of the toothing12. Once again, the recesses 14″ on one side of the blade back 11, whichare spaced equally apart from one another, are offset from the recesses15″ on the other side of the blade back 11, which are also spacedequally apart from one another; the offset corresponds to half thespacing between the recesses 14 and between the recesses 15″.

[0021] The invention is not limited to the exemplary embodimentsdescribed for the saw blade. For instance, in the portions a and b ofthe toothing 12, there can be more than one and two saw teeth 13,respectively. Nor is it compulsory that all the portions a and/or b ofthe toothing 12 each include the same number of saw teeth 13. Instead,the number of saw teeth can vary within the portions a and/or with theportions b_(z) The recesses 14 and 15 that are associated with theportions b of the teeth must then be varied accordingly in their width.

[0022] The saw blade need not necessarily be embodied as a saw bladethat can be fastened on one side in a power reciprocating saw. It canalso be provided with fastening means on both ends of the blade forreception in a power coping saw, as a further exemplary embodiment of apower tool.

1. A saw blade for power tools, in particular for power reciprocatingsaws, having a blade back (11) and a toothing (12), extending along thelower edge of the blade back, comprising many saw teeth (13) lined up insuccession, characterized in that in successive portions (a, b) of thetoothing (12), each with an integral number of saw teeth (13), the sawteeth (13) are embodied with the same tooth width (a_(z), b_(z)), whichhowever is different from the saw teeth (13) in the preceding orsucceeding portion (b, a) of the toothing (12).
 2. The saw blade ofclaim 1, characterized in that the tooth width (a_(z)) of the saw teeth(13) in one set of portions (a) of the toothing (12) is equivalent tothe thickness of the blade back (11), and the tooth width (b_(z))differing from it of the saw teeth (13) in the other portions (b) of thetoothing (12) is brought about by material removal or materialcompacting.
 3. The saw blade of claim 2, characterized in that insuccessive portions (b) of the toothing (12) with saw teeth (13) havingthe reduced tooth width (b_(z)), the material removal or materialcompacting is performed in alternation from one side and the other ofthe blade back (11).
 4. The saw blade of claim 3, characterized in thatthe saw teeth (13) with the reduced tooth width (b_(z)) are transposed,and the transposition is done toward the side of the blade back (11)remote from the material removal or material compacting.
 5. The sawblade of one of claims 2-4, characterized in that parallel recesses (14,15; 14′, 15′; 14″, 15″) spaced apart from one another are made in theblade back (11) on both sides of the blade back (11) and extend past thesaw teeth (13) as far as the underside, remote from the blade back (11),of the toothing (12), and that the recesses (14) on one side of theblade back (11) and the recesses (15) on the other side of the bladeback (11) are disposed offset from one another longitudinally of the sawblade.
 6. The saw blade of claim 5, characterized in that the recesses(14, 15) are extended as far as the upper edge (111), remote from thetoothing (12), of the blade back (11).
 7. The saw blade of claim 5,characterized in that the recesses (14′, 15′; 14′, 15″) end at adistance in front of the upper edge (111), remote from the toothing(12), of the blade back (11).
 8. The saw blade of one of claims 5-7,characterized in that the recesses (14, 15; 14′, 15′) are inclinedrelative to the toothing (12) at an acute angle (α) in the advancementdirection of the saw blade (11), and preferably the acute angle (α) isequivalent to the rake angle of the saw teeth (13).
 9. The saw blade ofone of claims 2-8, characterized in that successive portions (a, b) ofthe toothing (12) have in alternation one tooth of large tooth width(a_(z)) and two teeth (13) of reduced tooth width (b_(z)).
 10. The sawblade of one of claims 5-9, characterized in that the recesses (14, 15;14′, 15′; 14″, 15″) are cut into the blade back (11) and the toothing(12) before the transposition of the saw teeth (13).